Artificial material and process for making same



Patented Sept. 4, 1928.

UNITED STATES PATENT OFFICE.

LEON LILIENFELD, OF VIENNA, AUSTRIA.

ARTIFICIAL MATERIAL AND PROCESS FOR MAKING SAME.

No Drawing. Application filed June 3, 1926, Serial No. 113,583, and in Austria .Tune 20, 1925. Renewed July 26, 1923.

In my co-pending application No. 113,5t32, filed June 3, 1926, for artificial material and process for making same, a process 1s described, wherein sulphuric acid containing at least 55 per cent of H,SO,, preferably sulphuric acid containing to 85 per cent of H 80 is used as coagulating bath for viscose.

The present inventionis based upon the discovery that viscoses containing not more than 5 per cent of caustic alkali (calculated as NaOH), when brought into the form of an artificial materialsuch as threads, films, bands or plates, yield lustrous products when coa-gulated with sulphuric acid containing not less than 45, but less than 55 per cent of H 80 I Any viscose prepared according to any process or method known hitherto from analkali cellulose that has been matured as usual in the artificial silk art, for example for 72 hours, or that has notbeen matured at all or that has been matured fora shorter time than such as isusual in the artificial silk art, for example for- 3 to 48 hours, may

be used in the present process, provided that the viscose does not contain more than 5 per cent "of caustic alkali (calculated as NaOH).

This aim can be attained for example by dissolving the sulphidized mass either in water or in a causticsoda solution weak enough not to allow the total content of the final viscose in caustic soda. to exceed 5 per cent calculated on the weight of the final viscose solution.

Such viscose is brought into the form of an artificial material and coagulated by means of strong sulphuric acid, for example sulphuricacid containing 45 to 55 per cent of monohydrate. In most cases, for instance in manufacturing artificial threads or filaments, or films, or bands, or plates, this can be efiected in such a manner that the viscose is caused to pass through suitably formed openings into strong sulphuric acid, for instance acid of A5. to 55 per cent strength (calculated on H SOJ or into a bath containing 45 to 55 per cent of monohydrate. The sulphuric acid may be employed by itself or in admixture with one or more suitable inorganic substances, for example with another strong mineral acid such as hydrochloric acid, nitric acid or phosphoric acid, or with a neutral or acid acid, such as acetic acid or formic acid or.

lactic acid or oxalic acid. If a salt is added which is capable of reacting with the strong sulphuric acid under formation of an acid sulphate, or which mutually interacts with the sulphuric acid, the strength of the sulphuric acid should be so chosen that, after,

the amount required for the formation of the acid sulphate or for the mutual interaction is used up, the coagulating bath contains free sulphuric acid of the desired strength, but

for exampleat any rate not less than 45 parts by weight of monohydrate in 100 parts by weight of the recipitating bath.

I desired, there may be added to the viscose one or more suitable substances known in the viscose-silk art, for example glycerol or glucose or sodium sulphate or sodium sulphite or sodium bisulphite or ammonium sulphate or an alkali silicate or an alkali aluminate or ammonia.

The precipitating bath may be kept at room temperature or at a temperature exceeding room temperature, for example at 25 to 40 C., or at a temperature lower than room temperature, for example at 0 to 5 C., or even below 0 0., for example at from -1to -10C.--

The length of immersion of the thread or filament or plate or film or band in 'the strong sulphuric acid or in the bath containing it ma be varied within wide limits, for example" mm 3 to 60 centimetres and even more, for instance 1 to 2 meters.

If desired the thread or film or band may be stretched either immediately after its formation, i. e. in the precipitating bath containing, or consisting of, sulphuric acid, of

-45 to 55 r cent strength or subsequentl i. c. after it has been removed from the batli, i. e. between the precipitating bath and the collecting device, for instance bobbin or centrifuge.

Thethread or fihn or band or plate or coated or impregnated material may, after washing, be heated or steamed before or after drying.

The-process being 0 en to manifold variations, it is not inten ed to confine the invention to the following examples given for the practical carrying out of the process. v

. I (a). 100 parts by weight of sulphite-pulp or linters are impregnated with 900 to 2 000 parts by weight of a caustic soda solution of 18 per cent strength at 15 to 18 (1., and the mixture allowed to stand for 3 to 2 hours. parts by weight, and the residue comminuted by hand or in a suitable apparatus, for instance in a cooled shredder. minuted soda cellulose is then kept at room temperature for 60 to 72 hours, whereupon 30 to 60 parts by weight of carbon bisulphide.

- dissolved in 600-700 parts by weight of waprecipitating ter orin 400500 arts by weight of a caustic soda solution 0 1 to 1,3 percent strength. The viscose solution thus obtained is then fil- 'tered in a known manner through cottonwool or a dense cotton fabric or throu h both and freed from gas bubbles if any. fmmediately after, or after it has been allowed to ripen at 16-18 O. for a shorter (for example 12 hours to two days) or a longer (for example three to four days) time, the viscose is spun in a known manner into one of the following precipitating baths:

(1) Sulphuric acid of 60 B., or

(2) Sulphuric acid of 55 B., or

(3) A solution of 13,3 parts by weight of ammonium sulphate in 120 parts b weight of sulphuric acid of 55 B., to whic 1 9 tolO parts of sulphuric acid of 66 B. have been added, or L (4) A solution of 10 to 15 parts by weight of glucose in 190 to 185 parts by weight of sulphuric acid of 55 B. I

The temperature of the precipitating bath is kept at to 169 C., for instance at 8 C., orat 4to-8 C. The length of immersion in the coagulating bath of. the threads forming therein may be short for example 10 centimetres or long forinstance from 30 to 100 centimetres and more. They are then collected in a known manner on a bobbin or in a spinning centrifuge which ma be placed either close by the Then the mass is pressed to 300 The com-,

the coagulating bath is (1., for example 8 C., i v desired-t e speedath or at a distance from.

20 to 120 centimetres from the bath, whereupon the threads are washed and dried.

The threads ma known manner whi st they are in the precipitating bath, or after they 'ave been removed from the bath. This may be done for example either by choosing a more or less long distance between the bath and the col- "lecting device, or by. leading the threads over rods or hooks arranged in the bath or between the bath and the collecting device, or in the bath and between the bath and the collecting device.

The speed of spinning ma be varied within wide limits. As a ru e to which, however, the invention is not intended to be confined, it may be assumed that the upper limit of speed possible is dependent partly upon the temperature of the coagulatbe stretched in any ing bath, partly upon the length of immeris used at a for example atis 60 to 120, for example 80 centimetres, and

if the distance between the coagulating, bath and the collecting device, for example bobbin, is 60 to 150 centimetres, for instance 120 centimetres, and if the stretching given the thread between the coagulating bath and the collecting device is comparatively hi h,

and if the pump delivers about 2 to 3 on ie centimetres of viscose a minute, then excellent results are obtained with a speed of 18 to 26 meters a minute, or 30 meters a minute,

' but also a higher speed, for'example of 30 to 40 meters a minute may be employed if desired.

(2)- Ifall spinning conditions reniainthe same as in (1), except that the pump delivers 4 to 5 cubic centimetres of viscose a minute, then, if desired a speed up to 40 to 60 meters a minute may be employed.

(:3) If the spinning conditions are exactly as in (1), except that the temperature of lus- 4 to lus 25 may be up to 50 to 60 meters.

If in (1) the length of immersion or the distance between the coagulating bath and the collecting device or both are shortened, the speed may be increased.

Before being washed, the threads may be treated in any known manner with a precipitating bath known in the viscose-silk art, for example a solution of sodium bisulphate or sodium bisulphite or with dilute sulphuric acid or the like.

The washed threads may, before or after drying, be heated (for example at 100110 C.) or steamed.

They may also be treated with any desulphurating or bleaching agent known in the viscose art.

(b). The mode of operation is as in (0), except that 75 to 150 parts by weight of carbon bisulphide are employed for the sulphidizing of the soda-cellulose.

(c). The mode of operation is as in (a) or (b), with the difference that the soda-cellulose is pressed to 200 parts by weight.

[I (a) to (0).

Mode of operation as in Example I (w) to I (c), with the exception that the soda cellulose is not allowed to mature at all or allowed to mature for 1 to 48 hours, for example for 3 to 24 hours only.

According to the foregoing examples, it is possible to obtain artificial silk or staple fibre'which has a. considerably higher dry and wet tenacity than silk spun under same spinning conditions, but by means of chemicals customary 'in the viscose silk-art, for example by using a known precipitating bath. For example: it is not difiicult to produce artificial silk having a dry tenacity of more than 2 grammes per denier, even more than 2,5 grammes per denier, for example 2,8 grammes to 3 grammes and more per denier and a wet tenacity of 1,5 to 2 grammes per denier and more.

III.

A viscose prepared as described in Example I or II is caused to pass through a suitable hopper or slit in one of the coagulating liquors mentioned in Example I, and after having left the precipitating bath, is washed and dried in any known manner.

A cotton fabric is impregnated or filled or coated once or several times with a viscose prepared according to one of the methods described in Example I or II, for which purpose any suitable machine, such as a pad ding machine or a back filling machine or a spreading machine may be employed. To the viscose there may be added a filling substance, for instance talcum or china clay or a colouring matter or a pigment such as mica, or soot or a mineral colour or the like. The impregnated or coated material is, without being dried, o tionally in the stretched state, taken throug one of the precipitating baths described in Example I, whereupon the material is washed and dried.

In the foregoing examples, in the prepara-' tion of viscose, instead of wood pulp, there may be used bleached cotton, or cellulose treated in the cold or in the heat with dilute acids, for example hydrochloric or sulphuric acid, in short any kind of cellulosic bodies employed in, or proposed for the manufacture of viscose.

The expression artificial material in the description and claims is intended to mean: artificial threads and filaments of any kind, for example artificial silk, staple fibre, artificial cotton, artificial wool, artificial hair, films, plates, coatings and fillings of any kind.

The expression heating in the claims is intended to cover any known kind of heating, steaming included.

The statements in the description and claims regarding percentages relate to percentages by weight.

I claim:

l. lrocess for manufacturing artificial materials from viscose, which comprises bringing a viscose containing not more than 5 per cent of caustic alkali (calculated as NaOH), into the form of an artificial material arid acting upon it with sulphuric acid, containing not less than but less than per cent of sulphuric acid monohydrate.

2. Process for manufacturing artificial materials from viscose, which comprises bringing a viscose containi'n not more than 5 per cent of caustic alkali (calculated as NaOH), into the form of an artificial material and acting upon it with a coagulating bath, containing not less than 45 but less .than 55 per cent of sulphuric acid monohydrate.

ing not less than 45 but less than 55 per cent of sulphuric acid monohydrate.

5. Process for manufacturing artificial materials from .viscose, which comprises causing a viscose containing not more than 5'per cent of caustic alkali (calculated as NaOH), to pass through suitably formed openings into a coagulating bath which contains not less than 45 but less than 55 per cent of sulphuric acid monohydrate and at least one other inorganic substance.

- 6. Process for manufacturing artificial materials from viscose, which comprises causing a viscose containing not more than 5 per cent of caustic alkali (calculated as NaOH) to pass through a coagulating bath containing not less than but less than per cent of sulphuric acid monohydrate and giving the coagulated viscose a len h of immersion in the coagulating bath 0 30 to 200 centimeters.

7. Process for manufacturing artificial materials from viscose, which comprises causing a viscose containin not more than 5 per cent of caustic alkali (calculated as N aOH) to pass through suitably formed openings into a coagulating bath containing not less than 45 but less than 55 per cent of sulphuric acid monohydrate and stretching the coagulated material in the coagulating bath.

8. Process for manufacturing artificial materials from viscose, which comprises.

causing a viscose containing not more than 5 per .cent of caustic alkali (calculated as NaOH) to pass through suitably formed openings into a coagulating bath containin not less than 45 but less than 55 per cent 0% sulphuric acid monohydrate and stretching the coagulated material between the coagulating bath and the collecting device.

9. Process for manufacturing artificial materials from viscose, which comprises causing a viscose containin not more than 5 per cent of caustic alkali (calculated as NaOH) to pass through suitably formed openings into a coagulating bath containing not less than 45 but less than 55 per cent of sul huric acid monohydrate and stretching the -"coagulated material in the coagulating bath and between the coagulating bath and the collecting device.

10. Process for manufacturing artificial materials from viscose, which comprises causing a viscose containing not more than 5 percent of caustic alkali (calculated as NaOH) to pass. through suitably formed openings into a coagulating bath containin notless than 45 but less than 55 per cent 0 sulphuric acid monohydrate and heatinthe' artificial material after washing an dryin it.

l1. rocess for manufacturing artificial materials from viscose, which comprises bringing a viscose, prepared from an alkali cellulose which has been allowed to mature from naught to 48 hours, which viscose contains not more than 5 er'cent of caustic alkali (calculated as Na H), into the form of an artificial -material and acting u on it with sulphuric acid, containing not ess than 45 but less than 55 per cent of sulphuric acid monohydrate. v

12. Process for manufacturing artificial materials fromviscose, which comprises bringing a viscose, prepared from an alkali cellulose which has been allowed to mature from naught to- 48 hours, which viscose contains not more than 5 per cent of caustic alkali (calculated as NaOH), into ,the form of an artificial material and acting it with a coa lating bath, contain ng not less than 45 ut less than 55 per cent of sulphuric acid monohydrate.-

13. Process for manufacturing artificial materials from viscose, which comprises causing a viscose, prepared from an alkali cellulose which has been allowed to mature from naught to 48 hours, 'which viscose contains not more than 5 per cent of caustic alkali (calculated as NaOH), to pass through suit-ably formed openin s into sulphuric acid containin not lesst an 45 but ess than 55 per cent 0 sulphuric acid monohydrate.

14. Process for manufacturing artificial.-

materials from viscose, which comprises causing a viscose, prepared from analkah cellulose which has been allowed to mature from naught to 48 hours, which viscose conupon tains not more than 5 per cent of caustic alkali (calculated as NaOH), to pass through suitably formed openin s intoa co-' agulating bath containing not ess than 45 but less than 55 per cent of sulphuric acid 45 but less than 55 per cent of sulphuric acid monoh drate and at least one other inorganic su stance.

16. Process for manufacturing artificial materials from viscose, which comprises causing a viscose, prepared from an alkali cellulose which has been allowed to mature from naught to 48 hours, which viscose contains not more than 5 per cent of caustic alkali (calculated as NaOH), to pass through suitably formed openin s into a coagulating bath containing not ess than 45 but less than 55 per cent of sulphuric acid monohydrate and giving the coagulated viscose a length of immersion in the coagulating bath of 30 to 200 centimetres.

17. Process for manufacturing artificial materials from viscose, which comprises causing a viscose, prepared from an alkali monohydrate and stretching thecoagul ated material in the coagulating bath.

18. Proc ss for manufactu ng arti icial materials from viscose, which comprises causing a viscose, prepared from an alkali cellulose which has been allowed to mature from naught to 48 hours, which viscose contains not more than 5 per cent of caustic alkali (calculated as NaOH), to pass through suitably formed openings into a coagulating bath containing not less than 45- but less than 55 per cent of sulphuric acid monohydrate and stretching the coagulated material between the coagulating bath and the collecting device.

19. Process for manufacturing artificial materials from viscose, which comprises but less than 55'per cent of sulphuric acid monohydrate and stretching the coagulated material in the coagulating bath and between the coagulating'bath and the collecting device.

20. Process for manufacturing artificial materials from viscose, which comprises causing a viscose, prepared from an alkali cellulose which has been allowed to mature from naught to 48 hours, which viscose contains not more than 5 per cent of caustic alkali (calculated as 'NaOH), to pass through suitably formed openings into a coagulating bath containing not less than 45 but less than 55 per cent of sulphuric acid monohydrate and heatin the artificial material after washing and drying it.

In testimony whereof I affix my signature. 1

LEON LILIENFELD. 

